Lionel Messi scored twice as Barcelona came from behind to beat a 10-man Valncia at Camp Nou on Sunday to keep La Liga leaders Real Madrid in sight as the battle for the league title heats up.An action-packed first half at Camp Nou saw Barcelona trail Valencia after Mangala rose highest to head home Dani Prejo's corner before a quick fire response from Luis Suarez and Lionel Messi put the home side in front.Straight after Messi's coolly taken spot kick, former Barcelona Munir El Haddadi brought the visitors back on level with a tidy finish off Jose Gaya's perfect pass that went through Pique's legs. Two second half goals from Messi and former Valencia man Andre Gomes secured the much needed three points for the Catalans who have now cut Real's lead to two points. Zinedine Zidane's men do have a game in hand.Barcelona reverted to 3-4-3 for the visit of Valencia, who were spearheaded in attack by former Blaugrana striker Munir. Barcelona boss Luis Enrique named the same team that destroyed Paris Saint-Germain 6-1 in the Champions League last 16 a fortnight ago.Samuel Umtiti returned to Barca’s central defence alongside Gerard Pique and Javier Mascherano, while Andres Iniesta, Ivan Rakitic and Rafinha complemented Sergio Busquets in midfield. Up front, Neymar replaced Arda Turan as MSN were on full display.Valencia, meanwhile were missing Nani on the right wing, although Simone Zaza dropped to the substitutes’ bench for Munir, who spent the last two seasons in the Catalans’ first team. Munir scored 10 goals in 45 appearances for Barca’s first team between 2014 and 2016, before heading to Valencia as part of the deal that took Paco Alcacer to Camp Nou.First HalfValencia got on the front foot from the blast of the whistle when right-back Cancelo who playing as a winger, broke clear down his flank and ventured into the box, but Javier Mascherano managed to block the Portuguese's cross.Barcelona responded through Luis Suarez who sprung an awful Valencia offside trap only to see his point-blank finish pushed away by Diego Alves.After a lull in proceedings, Suarez unselfishly teed up Messi in the penalty area, but the Argentine's finish was scuffed off the line by Orellan, before Gaya jumped in front of Rafinha's rebound. Moments after Orellana's impeccable chest-control from a square ball in the Barca box and cutback was intercepted by Samuel Umtiti, Pique's deflected clearance only went as far as Carlos Soler, who forced Ter Stegen to push away his thumping volley.There were screams for a penalty by the home side after Cancelo and Neymar tangled near the byline in Valencia's box down the right. ThebBrazilian went down but the referee refused to buy his story. After 29 minutes of wait for the opener, Munir sprung Barca's high line but couldn't beat Ter Stegen one on one. Mangala then beat Rakitic in the air to power the resulting corner past the Barca goalkeeper with his head.Valncia's lead only lasted for six minutes as Suarez latched onto a simple throw, ran into the gap that opened up in the Valencia box before side-footing a pinballed finish past Alves for the equaliser. Mangala went from a hero to a villain with two yellow cards that got him sent off. First he brought down Messi on the edge of the Valencia box amd moments later was caught pulling back Suarez, who was clean through in the area. Messi stepped up and drove the ball straight down the centre of Alves' goal.Straight after Messi drove his penalty through the middle of Alves' goal, Valencia scored directly from the restart as Munir coolly finished off a break with Gaya providing the assist.Second HalfWith their home and numerical advantage, virtually all of Barca’s outfield players pushed up into Valencia’s half for the restart. Neymar latched onto a slide-rule pass down the left from Messi, but Alves made a fine stop to deny his countryman at his near post.Nonetheless, Messi fared better when he was sent through by Mascherano of all people as the No 10 proceeded to blast the ball past Alves.Barca refused to slow down, despite their lead, and were almost countered when Suarez missed his overhead kick, only for Munir to pay the price for being too elaborate when facing Pique near Ter Stegen’s penalty area.That was to be the away side’s final chance as Suarez was slipped in near the right-hand byline but slammed his effort into the side-netting. The No 9 also failed to guide the rebound from Messi’s saved strike into an empty net.Quietly going about his business was Neymar, who came a whisker away from scoring an identical free kick to his one against Paris Saint-Germain. However, he clipped the woodwork instead.Messi picked up a yellow card for dissent, ruling him out of Barca’s next game after the international break - against relegation-threatened Granada and not the likes of Sevilla and Madrid.The hosts finally found a fourth goal just before injury time as a quick-fire counter saw Neymar break down the left, evade a challenge and square the ball to Gomes, who found the roof of former teammate Alves’ net first time.